Track Checker Car
Track Checker Car
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A simple to make car that will quickly check for track defects. It is more sensitive to dips, twists, and changes in radius than the unaided eye.  The track checker car in the diagram above can easily be made out of a spare box car. An Athearn box car worked well for the original. First drill a 1/2" hole directly above the centre of one truck. This is easier if you remove the roof walk. You can use regular twist drills and slowly work up to 1/2" or your can drill a 1/8" pilot hole and follow it through with a 1/2" spade bit. The latter works particularly well with a drill press. Second, epoxy a piece of tubing into the centre of one truck. Use tubing as big as or bigger than the hole in the bottom of the box car, even if this means enlarging the hole in the truck. For an Athearn truck, the author used 1/8" tubing. Be sure the tubing is perfectly vertical when the truck is sitting on a horizontal surface. If you have a drill press available, you can drill a hole the size of the tubing into a flat block, force the tubing into the hole, and then set the truck over the tubing and resting on the block. After the epoxy is well set, trim off any tubing projecting from the bottom of the truck. Third, adjust the hole in the bottom of the box car so that the tubing slips easily into place and the tubing can move to any position in the 1/2" hole. Make the bottom end of the hole just a tiny bit larger than the tubing. This is easy if you have access to a set of number drills. Otherwise, some gentle filing with a small, round file is in order. Make the rest of the hole larger than the tubing to allow the tubing to move freely in all directions. Fourth, install the truck by pushing the tubing up through the holes. Then trim the tubing to length. The longer the tubing, the more sensitive the car is to errors in the track work. But for use in tunnels or helices, you may have to cut it off just above the roof of the boxcar. Once the tubing is trimmed, you can solder or epoxy on a flag, which can be as simple as a bent piece of wire. It is convenient to have the flag pointing directly forward or directly backwards when the wheels are straight. DO NOT try to simplify this process by simply bending over the top of the rod or tubing (it causes more trouble than it saves.) To use the car, push it along your track, preferably using a finger on top of the car. If tubing moves back and forth (pitch axis) you have some changes in grade, that is, dips and humps. If the tubing moves sideways (roll axis) you have some twists, that is, changes in how level the track is from side to side. If the flag turns (yaw axis), you have some changes in radius, and maybe even kinks. If the tubing remains stationary relative to the car, and the flag does not turn, then CONGRATULATIONS! You have some fine track work.
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